1. How is Soil Formed and How Long Does It Take? Soil formation is a long slow process. It's estimated that an inch of soil takes 500 to 1000 years to form. Soil is constantly being formed. It is also constantly being eroded. Stage One This is the rock pulverizing stage. Here the forces of wind, rain, freezing and thawing water, earthquakes, volcanos all work to slowly pulverize rocks into smaller partcles that can make up a soil. At the end of this stage we have most likely a combination of sand, silt and clay sized particles. These form a mineral soil like substance but are unable to support life. They are missing nitrogen. It may seem nitrogen should be the least of a being's worries. After all the air we breath is made up of about 78% nitrogen gas. The problem is that plants can not use nitrogen in this form. For them it needs to be converted to either ammonia which is a combination of nitrogen and hydrogen or nitrates - a combination of nitorgen and oxygen.

2. Stage Two This is the early stage of what we might call soil. Here we add some life, specifically lichens. Lichens are a symbiotic relationship of algae and fungus. The algae has the very important role of fixing the nitrogen, changing it from nitrogen gas to a form the plant can use. It also captures the sunlight and creates sugars and oxygen. The fungus provides a place for the algae to live, along with water and the mineral nutrients it needs. Lichens are very long lived - hundreds to thousands of years and they also further break down rock with acids they produce. About 8% of the earth is covered by lichens. Lichens are joined by mosses, bacteria, protozoa, and fungi. These form a complex cooperatve community that works to store nitrogen, nutrients and water to foster the growth of new plants. Stage Three At this time the little pockets of soil have formed to the extent that some larger plants, plants with roots can have a go at growing. The first pioneers will be short lived but as their bodies are added to the layers of soil forming the soil becomes more capable of supporting life. Humus builds and soil horizons begin to form. Stage Four The soils are developed enough to support thick vegetation 3. Dumping and decompusing 4. Biodegradable waste is a type of waste which can be broken down, in a reasonable amount of time, into its base compounds by micro-organisms and other living things, regardless of what those compounds may be. Biodegradable waste can be commonly found in municipal solid waste (sometimes called biodegradable municipal waste, or BMW) as green waste, food waste, paper waste, andbiodegradable plastics. Other biodegradable wastes include human waste, manure, sewage, and slaughterhouse waste. In the absence of oxygen, much of this waste will decay tomethane by anaerobic digestion. 5. Climate change impacts The main environmental threat from biodegradable waste is the production of methane . Uses of biodegradable waste Biodegradable waste can be used for composting or a resource for heat, electricity and fuel by means of incineration or anaerobic digestion.Swiss Kompogas and the DanishAIKAN process are examples of anaerobic digestion of biodegradable waste. While incineration can recover the most energy, anaerobic digestion plants retain the nutrients and compost for the soil and still recover some of the contained energy in the form of biogas. Kompogas produced 27 million Kwh of electricity and biogas in 2009. The oldest of the company's own lorries has achieved 1,000,000 kilometers driven with biogas from household waste in the last 15 years. 6. Trash falls into one of two categories: either biodegradable or non- biodegradable.While Biodegradable waste will eventually break down and become part of the earth and soil, like food scraps and paper. Non-biodegradable waste will NOTbreak down or at least NOT break down for many years. Examples of Non-biodegradable are plastics, metal and glass. Dangerous chemicals and toxins are also non-biodegradable, as are plastic grocery bags, plastic water bottles and other similar materials. Non-biodegradable trash has been a growing concern to environmentalists, but now is becoming a concern to anyone wanting to embrace a more eco-friendly lifestyle; as world population grows so does our waste. Its becoming increasingly important to understand what non- biodegradable waste is, as well as the effects that it has in on our planet. 7. Non-biodegradable trash that is discarded to be land filled will only accumulate. The most wide-reaching effect of non- biodegradable trash is the Pacific Garbage Patch; an area of the Pacific Ocean, which is heavily polluted with plastics and other waste. The patch extends over a very wide area, with estimates ranging from an area the size of the state of Texas to one larger than the continental United States; however, the exact size is unknown. It is estimated that unless consumers reduce current levels of non- biodegradable waste, the Pacific Garbage Patch will double in size in the next 10-20 years endangering the life of an infinite amount of marine animals. All hope is not lost, and there are ways to prevent the accumulation of non-biodegradable waste. The most common one available to everyone is to recycle. Another solution is to replace non- biodegradable materials with ones specifically designed to biodegrade; and also supporting companies that are striving to help our environment. Above all Say No To Plastic Bottles! Say No To Plastic Bags! 8. Major soil pollutants and their effect on human health Metal Source Effects Arsenic occurs naturally Chronic poisoning leads to a loss of appetite and weight, diarrhea, alternating with constipation, gastro intestinal disturbances, peripheral neuritis, conjunctivitis and sometimes skin cancer Cadmium mining, metallurgy chemical industry and electroplating leads to chronic poisoning and affects the proximal tubules of the kidney, causing formation of kidney stones Lead lead smelters storage battery lead poisoning can lead to severe mental retardation or death Mercury industrial wastes methyl mercury compounds are much more toxic than other forms of mercury, causes neurological problems and damages renal glomeruli and tubules Cyanides wastes from heat treatment of metals, dismantling of electroplating shops, etc. rapid death may follow due to exposure to cyanide as a result of inhibition of cellular respiration 9. Effects of soil pollution 10. 1.Industrial Activity: Industrial activity has been the biggest contributor to the problem in the last century, especially since the amount of mining and manufacturing has increased. Most industries are dependent on extracting minerals from the Earth. Whether it is iron ore or coal, the by products are contaminated and they are not disposed off in a manner that can be considered safe. As a result, the industrial waste lingers in the soil surface for a long time and makes it unsuitable for use. 2. Agricultural Activities: Chemical utilization has gone up tremendously since technology provided us with modern pesticides and fertilizers. They are full of chemicals that are not produced in nature and cannot be broken down by it. As a result, they seep into the ground after they mix with water and slowly reduce the fertility of the soil. Other chemicals damage the composition of the soil and make it easier to erode by water and air. Plants absorb many of these pesticides and when they decompose, they cause soil pollution since they become a part of the land. 11. 3. Waste Disposal: Finally, a growing cause for concern is how we dispose of our waste. While industrial waste is sure to cause contamination, there is another way in which we are adding to the pollution. Every human produces a certain amount of personal waste products by way or urine and feces. While much of it moves into the sewer the system, there is also a large amount that is dumped directly into landfills in the form of diapers. Even the sewer system ends at the landfill, where the biological waste pollutes the soil and water. This is because our bodies are full of toxins and chemicals which are now seeping into the land and causing pollution of soil. 4. Accidental Oil Spills: Oil leaks can happen during storage and transport of chemicals. This can be seen at most of the fuel stations. The chemicals present in the fuel deteriorates the quality of soil and make them unsuitable for cultivation. These chemicals can enter into the groundwater through soil and make the water undrinkable. 5. Acid Rain: Acid rain is caused when pollutants present in the air mixes up with the rain and fall back on the ground. The polluted water could dissolve away some of the important nutrients found in soil and change the structure of the soil. 12. Control of Soil Pollution 1. 1.Use of pesticides should be minimized. 2. Use of fertilisers should be judicious. 3. Cropping techniques should be improved to prevent growth of weeds. 4. Special pits should be selected for dumping wastes. 2.5. Controlled grazing and forest management. 6. Wind breaks and wind shield in areas exposed to wind erosin . 7. Planning of soil binding grasses along banks and slopes prone to rapid erosin. 8. Afforestation and reforestation. 13. Reducing Usage of Chemicals 1.Pesticides and fungicides are essential for plant growth but their overuse has led to soil pollution. Bio-fertilization and manures should be used instead of their chemical alternatives. Biofertilization is a process in which certain microorganisms are used to increase the fertility and growth capacity of soil. The process reduces the need for pesticides and fungicides. Manure, meanwhile, is always considered preferable to pesticides. In its organic form, manure has few negative effects on the ecological system. 2.Recycling is another way to reduce and control soil pollution. Recycling paper, plastics and other materials reduces the volume of refuse in landfills, another common cause of soil pollution. 14. 3.De-forestation, the cutting down of trees, causes erosion, pollution and the loss of fertility in the topsoil. Planting trees-- or re-forestation--helps prevent soil erosion and pollution. 4.Weeds soak up minerals in the soil. Reducing weed growth helps reduce soil pollution. One of the more common methods of reducing weed growth is covering the soil with numerous layers of wet newspapers or a plastic sheet for several weeks before cultivation. This prevents light from reaching the weeds, which kills them. 5.Designated pits should be used for the dumping of soil wastes. These wastes should be treated chemically and biologically to make them less toxic and hazardous. Biological treatment involves the use of anaerobic microorganisms, such as methanogens and acetogens, which help break down the soil wastes into a less toxic and biodegradable form. 15. Reuse is to use an item again after it has been used. This includes conventional reuse where the item is used again for the same function, and new-life reuse where it is used for a different function. In contrast, recycling is the breaking down of the used item into raw materials which are used to make new items. By taking useful products and exchanging them, without reprocessing, reuse help save time, money, energy, and resources. In broader economic terms, reuse offers quality products to people and organizations with limited means, while generating jobs and business activity that contribute to the economy. 16. Recyclable materials include many kindsof glass, paper, metal, plastic, textiles , and electronics. The composting or other reuse ofbiodegradable wastesuch as food or garden wasteis also considered recycling. Materials to be recycled are either brought to a collection center or picked up from the curbside, then sorted, cleaned, and reprocessed into new materials bound for manufacturing. 17. In the strictest sense, recycling of a material would produce a fresh supply of the same materialfor example, used office paper would be converted into new office paper, or used foamed polystyrene into new polystyrene. However, this is often difficult or too expensive (compared with producing the same product from raw materials or other sources), so "recycling" of many products or materials involves their reuse in producing different materials (e.g., paperboard) instead. Another form of recycling is the salvage of certain materials from complex products, either due to their intrinsic value (e.g.,lead from car batteries, or gold from computer components), or due to their hazardous nature (e.g., removal and reuse of mercury from various items). Critics dispute the net economic and environmental benefits of recycling over its costs, and suggest that proponents of recycling often make matters worse and suffer from confirmation bias. Specifically, critics argue that the costs and energy used in collection and transportation detract from (and outweigh) the costs and energy saved in the production process; also that the jobs produced by the recycling industry can be a poor trade for the jobs lost in logging, mining, and other industries associated with virgin production; and that materials such as paper pulp can only be recycled a few times before material degradation prevents further recycling. Proponents of recycling dispute each of these claims, and the validity of arguments from both sides has led to enduring controversy. 18. Reforestation Mountain valley and forest plantings have unique requirements. Species selection is dependent on elevation and slope aspect. Planting within an existing forest (or where a forest once existed) is called reforestation. Reforestation can: Increase wildlife habitat Provide for future forest production Diversify forest species composition Replace trees lost to insects, diseases or fire Many reforestation projects involve minimal site preparation and tree maintenance, and may involve planting large numbers of trees per acre due to expected mortality. Generally, irrigation is not used to supplement natural moisture, but use of mulch is effective. These publications offer more information on planning, designing and preparing sites for planting; designing windbreaks; and planting to promote wildlife. 19. How does reforestation prevent soil erosion? Reforestation is to plant trees in forests that have been deforested. The roots of the trees hold the soil together therefore not having soil erosion. But soil erosion can still be done through humans, animals and other elements. 20. Soil conservation is a set of management strategies for prevention of soil being eroded from the Earths surface or becoming chemically altered by overuse, acidification,salinization or other chemical soil contamination. It is a component of environmental soil science. Decisions regarding appropriate crop rotation, cover crops, and planted windbreaks are central to the ability of surface soils to retain their integrity, both with respect to erosive forces and chemical change from nutrient depletion. Crop rotation is simply the conventional alternation of crops on a given field, so that nutrient depletion is avoided from repetitive chemical uptake/deposition of single crop growth. 21. Tree plantings benefit land and people by: Protecting property and livestock from wind Restoring or enhancing natural beauty Reducing soil erosion and improving crop yields Providing food and cover for wildlife Increasing property values Improving forest health Reducing water evaporation, preserving winter moisture, and protecting and improving water quality Controlling drifting snow Reducing atmospheric carbon dioxide Reducing heating and cooling costs (by providing protection from the sun and wind, trees can reduce energy costs by as much as 30 percent) Protecting livestock from the elements, maintaining and improving livestock weight, and reducing calving losses Increasing our supply of renewable resources 22. Some factors to consider in planning a tree planting, whether in the mountains or on the plains or whether it is designed to control wind or snow, or benefit wildlife: Location Elevation, slope and aspect Soil type and alkalinity Prevailing wind direction(s) Weed control methods Supplemental irrigation Snow drifting Power lines Planting size and shape Species selection Site preparation methods Underground utility locations Past land uses 23. In agriculture, a Terrace is a piece of sloped plane that has been cut into a series of successively receding flat surfaces or platforms, which resemble steps, for the purposes of more effective farming. This type of landscaping, therefore, is called terracing. Graduated terrace steps are commonly used to farm on hilly or mountainous terrain. Terraced fields both decrease erosion and surface runoff, and may be used to support growing crops that require irrigation, such as rice. The rice terraces of the Philippine Cordilleras have been designated as UNESCOWorld Heritage Site because of the significance of this technique. 24. Terraced farmland in Peru, adopted by the Inca. 25. Terraced hay fields in the Upper Mississippi River basin during the 1930s. 26. Jatiluwih rice terrace in Bali, Indonesia. 27. The Banaue Rice Terraces in Ifugao, Philippines. 28. Rice cultivation, Lower Himalayas, Nepal. 29. Terraced fields in Sa Pa, Vietnam. 30. No-till farming (also called zero tillage or direct drilling) is a way of growing crops or pasture from year to year without disturbing the soilthrough tillage. No-till is an agricultural technique which increases the amount of water that infiltrates into the soil and increases organic matter retention and cycling of nutrients in the soil. In many agricultural regions it can reduce or eliminate soil erosion. It increases the amount and variety of life in and on the soil, including disease-causing organisms and disease suppression organisms. The most powerful benefit of no-tillage is improvement in soil biological fertility, making soils more resilient. Farm operations are made much more efficient, particularly improved time of sowing and better trafficability of farm operations. 31. Tilling is used to remove weeds, shape the soil into rows for crop plants and furrows for irrigation. This leads to unfavorable effects, likesoil compaction; loss of organic matter; degradation of soil aggregates; death or disruption of soil microbes and other organisms including mycorrhiza, arthropods,and earthworms;[1] and soil erosion where topsoil is washed or blown away. No- till farming avoids these effects by excluding the use of tillage. With this way of farming, crop residues or other organic amenities are retained on the soil surface and sowing/fertilizing is done with minimal soil disturbance. Continuous no-till needs to be managed very differently in order to keep or increase yield on the field. Residue, weeds, equipment, crop rotations, water, disease, pests, and fertilizer management are just some 32. Contour ploughing or contour farming the farming practice of ploughing and/or planting across a slope following its elevation contour lines. These contour lines create a water break which reduces the formation of rills and gullies during times of heavy water run-off; which is a major cause of soil erosion. The water break also allows more time for the water to settle into the soil. In contour plowing, the ruts made by the plow run perpendicular rather than parallel to slopes, generally resulting in furrows that curve around the land and are level. This method is also known for preventing tillage erosion.[Tillage erosion is the soil movement and erosion caused by tilling a given plot of land.[3] A similar practice is contour bunding where stones are placed around the contours of slopes. Soil erosion prevention practices such as this can drastically decrease negative affects associated with soil erosion such as reduced crop productivity, worsened water quality, lower effective reservoir water levels, flooding, and habitat destruction.[4] Contour farming is considered an active form of sustainable agriculture. 33. Crop rotation is the practice of growing a series of dissimilar/different types of crops in the same area in sequential seasons. Crop rotation gives various nutrients to the soil. A traditional element of crop rotation is the replenishment of nitrogen through the use ofgreen manure in sequence with cereals and other crops. Crop rotation also mitigates the build-up of pathogens and pests that often occurs when one species is continuously cropped, and can also improve soil structure and fertility by alternating deep-rooted and shallow-rooted plants. Crop rotation is one component of polyculture. 34. The soil pH is a measure of the acidity or alkalinity in soils. pH is defined as the negative logarithm (base 10) of the activity of hydronium ions (H+ or, more precisely, H 3O+ aq) in asolution. In water, it nomally ranges from -1 to 14, with 7 being neutral. A pH below 7 is acidic and above 7 is alkaline. Soil pH is considered a master variable in soils as it controls many chemical processes that take place. It specifically affects plant nutrient availability by controlling the chemical forms of the nutrient. The optimum pH range for most plants is between 5.5 and 7.0,[1] however many plants have adapted to thrive at pH values outside this range. 35. Global variation in soil pH. Red = acidic soil. Yellow = neutral soil. Blue = alkaline soil.Black = no data 36. Denomination pH range Ultra acid < 3.5 Extreme acid 3.54.4 Very strong acid 4.55.0 Strong acid 5.15.5 Moderate acid 5.66.0 Slight acid 6.16.5 Neutral 6.67.3 Slightly alkaline 7.47.8 Moderately alkaline 7.98.4 Strongly alkaline 8.59.0 Very strongly alkaline > 9.0 Classification of soil pH ranges The United States Department of Agriculture Natural Resources Conservation Service, formerly Soil Conservation Service classifies soil pH ranges as follows: 37. Soils can process and contain considerable amounts of water. They can take in water, and will keep doing so until they are full, or until the rate at which they can transmit water into and through the pores is exceeded. Some of this water will steadily drain through the soil (via gravity) and end up in the waterways and streams, but much of it will be retained, away from the influence of gravity, for use of plants and other organisms to contribute to land productivity and soil health. 38. Soil water retention Pores (the spaces that exist between soil particles) provide for the passage and/or retention of gasses and moisture within the soil profile. The soil's ability to retain water is strongly related to particle size; water molecules hold more tightly to the fine particles of a clay soil than to coarser particles of a sandy soil, so clays generally retain more water.[1]Conversely, sands provide easier passage or transmission of water through the profile. Clay type, organic content, and soil structure also influence soil water retention.[2] The maximum amount of water that a given soil can retain is called field capacity, whereas a soil so dry that plants cannot liberate the remaining moisture from the soil particles is said to be at wilting point.[1] Available water is that which the plants can utilize from the soil within the range of field capacity and wilting point. The role of soil water retention is profound; its effects are far reaching and relationships are invariably complex. This section focuses on a few key roles and recognizes that it is beyond the scope of this discussion to encompass all roles that can be found in the literature. 39. Accumulation of excess salts in the root zone resulting in a partial or complete loss of soil productivity is a worldwide phenomenon. The problems of soil salinity are most widespread in the arid and semi- arid regions but salt affected soils also occur extensively in sub- humid and humid climates, particularly in the coastal regions where the ingress of sea water through estuaries and rivers and through groundwater causes large-scale salinization. Soil salinity is also a serious problem in areas where groundwater of high salt content is used for irrigation. The most serious salinity problems are being faced in the irrigated arid and semi-arid regions of the world and it is in these very regions that irrigation is essential to increase agricultural production to satisfy food requirements. However, irrigation is often costly, technically complex and requires skilled management. Failure to apply efficient principles of water management may result in wastage of water through seepage; over- watering and inadequate drainage result in water logging and salinity problems which reduce the soil productivity, eventually leading to loss of cultivable land. 40. soil organism, any organism inhabiting the soil during part or all of its life. Soil organisms, which range in size from microscopic cells that digest decaying organic material to small mammals that live primarily on other soil organisms, play an important role in maintaining fertility, structure, drainage, and aeration of soil. They also break down plant and animal tissues, releasing stored nutrients and converting them into forms usable by plants. Some soil organisms are pests. Among the soil organisms that are pests of crops are nematodes, slugs and snails, symphylids, beetle larvae, fly larvae, caterpillars, and root aphids. Some soil organisms cause rots, some release substances that inhibit plant growth, and others are hosts for organisms that cause animal diseases. soil organism, any organism inhabiting the soil during part or all of its life. Soil organisms, which range in size from microscopic cells that digest decaying organic material to small mammals that live primarily on other soil organisms, play an important role in maintaining fertility, structure, drainage, and aeration of soil. They also break down plant and animal tissues, releasing stored nutrients and converting them into forms usable by plants. Some soil organisms are pests. Among the soil organisms that are pests of crops are nematodes, slugs and snails, symphylids, beetle larvae, fly larvae, caterpillars, and root aphids. Some soil organisms cause rots, some release substances that inhibit plant growth, and others are hosts for organisms that cause animal diseases. 41. Indigenous crops Planting of native crops is known to be beneficial for soil conservation.if non- native plants are grown , the fields should be bordered by indigenous crops to prevent soil erosion and achieve soil conservation.a